Description du sujet de thèse

This doctoral project aims to experimentally investigate the physics of interfacial instabilities in immiscible binary liquids as the interfacial tension approaches zero. The program will focus primarily on the Rayleigh-Plateau instability (liquid jet/column) and then on the Kelvin-Helmholtz instability (due to a tangential stress jump), working at controlled temperatures approaching the miscible state.
Liquid jets will be produced by destabilizing the interface between two immiscible phases using the radiation pressure of a continuous-wave laser. By increasing the beam power, these jets form optically stabilized columns upon contact with the cell floor, which destabilize according to the Rayleigh-Plateau mechanism once the laser is switched off. Finally, the aim will be to induce a light-triggered Kelvin-Helmholtz instability in these liquid columns using flows induced by two beams propagating in opposite directions. The objective is to study all of these instabilities as a function of the decrease in interfacial tension up to the miscibility limit.
The candidate is expected to have a strong background in physics of fluids and soft matter; background in optics and laser-fluid interaction will be a plus. The candidate is also expected to be curious in theoretical and numerical developments as he will interact with other labs for quantitative comparisons between experiments and models.

Contexte de travail

The Laboratory LOMA comprises a single site and conducts fundamental, experimental, and theoretical research in Soft and Condensed Matter Physics and Optics. The Optofluidics group within the Soft Matter and Biophysics team develops experimental and theoretical research on laser/matter interactions, whether mechanical, fluidic, thermal, or photochemical; this project utilizes the first two components, which have been under development for several years.